Cutting traces to unlock button 6 is the best way, I kind of regret now I didn't make it easier with revision 4.2.
Another option is to install the CPS2 connector on the JAMMA extension and use the CPS2 kick harness between the HAS and the JAMMA extension.
Just received my extensions today and had some questions to clarify what is needed to allow 6 button operation. I had some discussions on discord about this and it sounded like others may benefit from a quick summary on each version and what is needed.
HAS v4.0 -> extension -> PCB:
I don't see anything in the HAS v4.0 manual about enabling button 6 for player 1/2 on the Jamma harness. Is this possible, or is it enabled by default? I only see jumper JP2 (advanced use only) to disable buttons 4/5, but nothing to enable/disable button 6. Would this scenario require one of the bottom two setups on the diagram, depending on if the extension has the CPS2 connector on it?
HAS v4.1 -> extension -> PCB:
I see information in the manual about the dips for p1/2 buttons 4/5/6, but it doesn't mention cutting a trace like the v4.2 manual indicates. Is this simply not documented in this manual, or is the trace cut not necessary on the v4.1? Once buttons 4/5/6 dips are enabled on the HAS, and also enabled on the extension, it appears that would allow the top setup on the diagram?
HAS v4.2 -> extension -> PCB:
Here I see information on enabling the dips for p1/2 buttons 4/5/6, which require a trace cut to enable the button 6 dip to take effect. Once the trace is cut and buttons 4/5/6 dips are enabled on the HAS, and also enabled on the extension, it appears that would allow the top setup on the diagram?
Also on the v4.2, and possibly on the v4.1 (depending on if a trace cut is needed), would cutting that trace cause any problems with using the HAS without the extensions as long as the button 6 dips are switched off? I assume cutting the trace simply enables those button 6 DIPS and doesn't permanently enable button 6 with no way to disable it?
Other Superguns (without button 4/5/6 on the jamma edge), or if a user doesn't want to modify the HAS by cutting the trace for button 6:
These would require one of the bottom two setups on the diagram, depending on if the CPS2 header is installed.
Thanks in advance for the clarification!